story: The stated clauses of the Nazi-Soviet non-aggression pact were a guarantee of non-belligerence by each party towards the other, and a written commitment that neither party would ally itself to, or aid, an enemy of the other party. In addition to stipulations of non-aggression, the treaty included a secret protocol that divided territories of Romania, Poland, Lithuania, Latvia, Estonia, and Finland into German and Soviet "spheres of influence", anticipating potential "territorial and political rearrangements" of these countries. Thereafter, Germany invaded Poland on 1 September 1939. After the Soviet–Japanese ceasefire agreement took effect on 16 September, Stalin ordered his own invasion of Poland on 17 September. Part of southeastern (Karelia) and Salla region in Finland were annexed by the Soviet Union after the Winter War. This was followed by Soviet annexations of Estonia, Latvia, Lithuania, and parts of Romania (Bessarabia, Northern Bukovina, and the Hertza region). Concern about ethnic Ukrainians and Belarusians had been proffered as justification for the Soviet invasion of Poland. Stalin's invasion of Bukovina in 1940 violated the pact, as it went beyond the Soviet sphere of influence agreed with the Axis.
questions: When did Germany invade Poland?
questions: When did the agreement with the Soviet and Japan take place?
questions: What did Stalin do?
questions: When was that?
questions: What was the goal of the Nazi-Soviet pact?
questions: What was the written agreement about?
questions: What areas were divided?
questions: What territories were annexed by the Soviet?
questions: And then where?
questions: What was the justification for invading Poland?
answers: 1 September 1939
answers: Germany invaded Poland on 1 September 1939
answers: 16 September
answers: After the Soviet–Japanese ceasefire agreement took effect on 16 September
answers: ordered his own invasion of Poland
answers: Stalin ordered his own invasion of Poland on 17 September
answers: 17 September
answers: Stalin ordered his own invasion of Poland on 17 September
answers: guarantee of non-belligerence by each party
answers: The stated clauses of the Nazi-Soviet non-aggression pact were a guarantee of non-belligerence by each party towards the other, and a written commitment that neither party would ally itself to, or aid, an enemy of the other party. 
answers: neither party would ally itself to, or aid, an enemy of the other party.
answers: written commitment that neither party would ally itself to, or aid, an enemy of the other party.
answers: Romania, Poland, Lithuania, Latvia, Estonia, and Finland
answers: divided territories of Romania, Poland, Lithuania, Latvia, Estonia, and Finland 
answers: Part of southeastern (Karelia) and Salla region in Finland
answers:  Part of southeastern (Karelia) and Salla region in Finland were annexed by the Soviet Union
answers: Estonia, Latvia, Lithuania, and parts of Romania (Bessarabia, Northern Bukovina, and the Hertza region).
answers:  followed by Soviet annexations of Estonia, Latvia, Lithuania, and parts of Romania (Bessarabia, Northern Bukovina, and the Hertza region).
answers: Concern about ethnic Ukrainians and Belarusians
answers: Concern about ethnic Ukrainians and Belarusians had been proffered as justification for the Soviet invasion of Poland